Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 220708
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
300 AM EDT FRI AUG 22 2014

.SYNOPSIS...
TODAY WILL BRING YET ANOTHER DAY OF UNSEASONABLE HEAT AND HUMIDITY.
SOME RELIEF MAY COME WITH A COLD FRONT ON SATURDAY BUT THE RETURN
OF TRUE SEASONABLE WEATHER PROBABLY WON`T BE UNTIL SUNDAY. MUCH
OF THE UPCOMING WEEK LOOKS SEASONABLE AND RAIN-FREE.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1000 PM THURSDAY...THUNDERSTORMS SURGED SOUTHEASTWARD INTO
NORTHERN NORTH CAROLINA MORE QUICKLY THAN EXPECTED...BUT A DRIER
AIRMASS THROUGHOUT THE 950-800 MB LAYER AND INCREASING DISTANCE FROM
THE UPPER DISTURBANCE MEANS THESE STORMS ARE DRYING UP. IT REMAINS
POSSIBLE AS THE UPPER DISTURBANCE REACHES SE NORTH CAROLINA LATE
TONIGHT THAT ISOLATED SHOWERS COULD REDEVELOP AS SHOWN ON THE 23Z
HRRR RUN. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS...

CONVECTION ALONG THE COAST HAS DIED AWAY LEAVING A MERGED
OUTFLOW/SEABREEZE BOUNDARY EASILY DISCERNIBLE ON RADAR IMAGERY FROM
NEAR ELIZABETHTOWN TO DILLON...MARION...AND INTO WESTERN GEORGETOWN
COUNTY. VISIBLE SATELLITE IMAGERY SHOWS NO CUMULUS CLOUDS ALONG THE
BOUNDARY SUGGESTING LIFT IS INSUFFICIENT TO PUSH PARCELS TO THEIR
LCL...LET ALONE THEIR LFC! DRY WEATHER IS ANTICIPATED THROUGH THE
EVENING HOURS WITH JUST SOME CIRRUS IN A NORTHWEST FLOW ALOFT.

IN THE UPPER LEVELS HIGH PRESSURE IS CENTERED OVER NEW ORLEANS WHILE
A SERIES OF SHORTWAVES HELPS AMPLIFY A TROUGH OFF THE NEW ENGLAND
COAST. ONE SUBTLE SHORTWAVE TROUGH MOVED OFF THE CAROLINA COAST A
FEW HOURS AGO...WHILE A SECOND DISTURBANCE UPSTREAM ACROSS
SOUTHWESTERN VIRGINIA IS HELPING INDUCE THUNDERSTORM ACTIVITY THERE.
MODELS CONFIRM SIMPLE LINEAR EXTRAPOLATION BRINGING THIS NEXT UPPER
DISTURBANCE SOUTHEASTWARD AND ACROSS SOUTHEASTERN NORTH CAROLINA
EARLY FRIDAY MORNING...5-8 AM EDT. LAPSE RATES ALOFT WILL CERTAINLY
BE STEEP ENOUGH TO SUPPORT CONVECTION...HOWEVER RATHER DRY AIR
LURKING WITHIN THE 950-800 MB LAYER SHOULD MAKE IT TOUGH FOR MUCH
CONVECTION TO SURVIVE THIS FAR SOUTHEASTWARD.

LOWS TONIGHT SHOULD REACH 73-76 FOR MOST AREAS...WITH 500-1000 FOOT
WIND SPEEDS ARGUING FOR ONLY A SMALL POTENTIAL FOR FOG.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...BACKDOOR COLD FRONT PUSHES THROUGH ON SATURDAY.
MOS NUMBERS ARE GENERALLY SPREAD BY 5 DEGREES WITH THE MAV WARMER OF
THE TWO. HAVE BASICALLY SPLIT THE DIFFERENCE...THE ACTUAL CAA LAGS
AND THE `COOLING` MAY BE MORE A FUNCTION OF FAIRLY EXTENSIVE CLOUD
COVER ASSOC WITH FROPA. MOS POPS ARE SURPRISINGLY LOW
AREA-WIDE...GENERALLY SLIGHT CHANCE TO LOWEST CHANCE RANGE. GIVEN
THE ANTECEDENT WARM AND HUMID AIRMASS IN PLACE PREFER THE 40-ISH
POPS CLOSE TO PREVIOUS FORECAST. MORE SEASONABLE AND LESS HUMID AIR
STARTS CREEPING IN SATURDAY NIGHT INTO SUNDAY. THE MOISTURE HOWEVER
IS SLOWER TO ADVECT OFF TO THE SOUTH. CLOUDS MAY THUS HANG IN ON
SUNDAY AND SOME SLIGHT CHANCE POPS WILL REMAIN IN THE
FORECAST...SLIGHTLY FAVORING COASTAL AND SOUTHERN LOCALES WHICH ARE
CLOSER TO THE BOUNDARY.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 3 AM FRIDAY...DRYING BECOMES PRONOUNCED ON MONDAY AS HIGH
PRESSURE WEDGE PUSHES FRONT AND ITS ASSOC MOISTURE EVEN FURTHER TO
THE SOUTH. MEANWHILE BUILDING UPPER RIDGE EXPANDS ACROSS MS AND OH
VALLEY REGIONS BRINGING A NORTHERLY FLOW LOCALLY. THIS WILL BE IN
PLACE THROUGH WEDNESDAY AND SOME VERY PLEASANT WEATHER IS EXPECTED.
BOTH RIDGES WEAKEN ON WEDNEDAY WHICH MAY ALLOW SOME LOW LEVEL
MOISTURE RETURN IN THE FORM OF NOTICEABLY MORE HUMID AIR...BUT STILL
TOO SHALLOW TO SUPPORT ANY MEANINGFUL PRECIP CHANCES.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...VFR CONDITIONS MAY GIVE WAY TO PATCHES OF MVFR VSBYS
OVERNIGHT AS CALM AND HUMID CONDITIONS SUPPORT SOME PATCHY MVFR BR.
ELSEWHERE...EXPECT THICKENING MID/HIGH CLOUDS TO KEEP VSBYS FROM
DROPPING BELOW MVFR. VSBYS WILL IMPROVE TO VFR SOON AFTER 12Z WITH
WNW WINDS AROUND 5 KTS THIS MORNING. AS THE SEA BREEZE MOVES
ONSHORE...WINDS ALONG THE COAST WILL BECOME S-SW AROUND 10 KT. NOT
EXPECTING MUCH IN THE WAY OF AFTN CONVECTION OTHER THAN SOME
ISOLATED SEA BREEZE STORMS POSSIBLY DEVELOPING AFTER 18Z. WILL
INCLUDE VCTS FOR THE COASTAL SITES ATTM...EVENTHOUGH CONFIDENCE
IS NOT AS HIGH LIKE PREVIOUS DAYS. THIS MAINLY DUE TO THE
INFLUENCE OF THE UPPER HIGH PRESSURE RIDGE WHICH TENDS TO SUPPRESS
CONVECTION.

EXTENDED OUTLOOK...CHC AFTERNOON/EVENING SHRA/TSRA THROUGH SUNDAY.
EXPECT VFR MON/TUE WITH HIGH PRESSURE OVER THE EAST COAST.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 PM THURSDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS...

THE PRESSURE PATTERN OVER THE CAROLINAS IS QUITE WEAK THIS EVENING.
LOW PRESSURE IS LOCATED ACROSS THE PLAINS STATES AND HIGH PRESSURE
IS WELL OFFSHORE. AN OLD STATIONARY FRONT HAS DECAYED TO A SIMPLE
LOW PRESSURE TROUGH INLAND. THIS BOUNDARY HAS MERGED WITH TODAY`S
SEABREEZE AND EARLIER THUNDERSTORM OUTFLOWS AND IS NOW LOCATED JUST
EAST OF INTERSTATE 95. SOUTHWEST WINDS AROUND 10 KNOTS SHOULD VEER A
LITTLE MORE WESTERLY OVERNIGHT...WITH SEAS AROUND 2 FEET. THE
POTENTIAL FOR FURTHER THUNDERSTORM ACTIVITY IS RATHER LOW...HOWEVER
AN UPPER LEVEL DISTURBANCE CURRENTLY PRODUCING THUNDERSTORMS ACROSS
SOUTHWESTERN VIRGINIA WILL SWEEP SOUTHEASTWARD AND MAY AFFECT THE
CAPE FEAR AREA BEGINNING AROUND 5 AM.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...THE COMBINATION OF A SURFACE TROUGH RIGHT ALONG
THE COAST EARLY SATURDAY AND A COLD FRONT SLIDING NORTH TO SOUTH
ACROSS THE REGION WILL LEAD TO A LIGHT WEST WIND THAT SHOULD START
VEERING FIRST OVER NORTHERN ZONES IN THE EVENING AND THEN FARTHER
SOUTH OVERNIGHT. THIS SENSE OF TIMING MAY NEED TWEAKING HOWEVER AS
MODELS ARE HAVING A LITTLE TROUBLE RESOLVING THE TWO BOUNDARIES. AT
LEAST A TURN TO THE NORTH LOOKS CERTAIN BY SATURDAY NIGHT AND A
GRADUAL INCREASE IN WIND SPEED AND THUS WAVE HEIGHTS SHOULD GET
UNDERWAY. SUNDAY WILL BRING A RATHER ATYPICAL NORTHEASTERLY FLOW
WITH A LITTLE BIT OF GUSTINESS AS HIGH PRESSURE BUILDS IN FROM THE
NORTH. SCEC TOUGH TO RULE OUT OVER NORTHERN ZONES.

LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 3 AM FRIDAY...RATHER UNUSUAL NORTHEASTERLY SURGE OF HIGH
PRESSURE TO CONTINUE THROUGH THE PERIOD WITH LITTLE CHANGE. THE
PERSISTENCE OF THE FETCH IN BOTH TIME AND SPACE COULD LEAD TO SOME
ADVISORY-WORTHY 6 FT SEAS BUT WIND SPEEDS WILL TEND TO STAY
SUB-ADVISORY. ALSO INTERESTING BUT HIGHLY UNCERTAIN IS THE
POSSIBILITY OF TROPICAL SYSTEM WELL OFFSHORE. NO DIRECT IMPACTS
EXPECTED AT THIS POINT BUT ITS RELATED SWELLS COULD BE RADIATING
THIS WAY BY THE END OF THE PERIOD OR JUST BEYOND.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...MBB
NEAR TERM...MJC
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DCH/BJR









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